1. Field of the Invention
This invention relates to an ink rail for supplying ink to a fountain roller in an ink supplying device of a printing press.
2. Description of the Background Art
Many ink rails of an ink supplying device are conventionally known as shown in Japanese Patent Laid-Open Publication No. 1-229633 (prior art 1), etc. Namely, an ink rail body of an ink rail is opposed to an outer circumferential surface of a fountain roller so as to cover this outer circumferential surface. An ink supplying surface as a concave curved surface for supplying ink and having a relatively long arc is formed along the outer circumferential surface of the fountain roller. An ink supplying pipe is normally connected to the ink rail body and extends from an ink pump for supplying the ink to a side opposed to the ink supplying surface as a concave curved face. An ink discharge port is opened to an ink supplying surface side. An ink guide path for connecting the ink supplying pipe and the ink discharge port is arranged between the ink supplying pipe and the ink discharge port.
The ink sent out by the ink pump reaches the ink discharge port through the ink guide path, and is transferred to the outer circumferential surface of the fountain roller by rotating the fountain roller. The ink is further transferred to a roller arranged downstream in contact with the fountain roller.
The ink rail is constructed such that the ink supplying surface can be separated from the outer circumferential surface of the fountain roller to clean the ink supplying surface, etc. For example, in a device disclosed in Japanese Patent Laid-Open Publication No. 1-229633 (U.S. Pat. No. 2,567,269) as the prior art 1, a supporting member is supported by bearings arranged in both end portions in a longitudinal direction of the supporting member and having an eccentric structure able to be angularly displaced. The ink rail body is arranged on an adjusting guide face of a pedestal arranged in the supporting member so as to adjust a movement of the ink rail body. This device is constructed such that the ink supplying surface arranged in the ink rail body can be opposed to the outer circumferential surface of the fountain roller at a suitable distance in an operating position, and can be selectively located between the operating position in proximity to the outer circumferential surface of the fountain roller and an unoperating position separated from the outer circumferential surface of the fountain roller.
The distance between the ink supplying surface of the ink rail body and the outer circumferential surface of the fountain roller is adjusted by moving a supporting position of the supporting member. The supporting position of the supporting member is moved by approaching and separating the ink rail body attached to the adjusting guide face of the pedestal arranged in the supporting member with respect to the outer circumferential surface of the fountain roller, and angularly displacing the bearings of the eccentric structure.
In the ink rail disclosed in the. prior art 1, the ink can be supplied over the entire width of a printing face. However, in the conventional ink rail in the printing press capable of performing a printing operation to wide web paper, the length of an arc of the ink supplying surface of the ink rail body is relatively long and mass of the ink rail body is increased in giving rigidity to this ink rail body so that operability is bad. While the printing press is used for a long time, the ink rail is flexed by a secular distortion. Further, the inkrail rail is flexed by the influence of a pressure caused by the ink existing within a distance formed between the ink supplying surface and the outer circumferential surface of the fountain roller during the operation of the printing press. Thus, with respect to a slight distance to be precisely set and maintained between the outer circumferential surface of the fountain roller and the ink supplying surface of the ink rail body having the relatively long arc, a distance near an end portion of the ink rail in its longitudinal direction and a distance near a central portion and its peripheral portion are gradually different from each other. As a result, a problem exists in that the ink supply becomes unstable and printing quality is reduced.
When the ink supplying surface is constructed by the concave curved surface having the relatively long arc, upper and lower end portions of the arc of the ink supplying surface in its longitudinal direction easily come in contact with the outer circumferential surface of the fountain roller during an adjusting operation when the distance is adjusted by a combination of the movement of the ink rail body on the supporting member and the movements of angular displacement centers of the eccentric bearings of the supporting member. Accordingly, a problem exists in that skill is greatly required and a long working time is required.
Further, in a worst case, there is a possibility of mutual damage caused by operating the printing press while the ink supplying surface of the ink rail body comes in contact with the outer circumferential surface of the fountain roller.
To prevent occurrences of these problems, the supporting member and the ink rail body are reprocessed and new parts are exchanged and attachments of the respective members are readjusted and reassembled, etc. so that large repair countermeasures are required. In addition to this, when the ink rail body is assembled into the supporting member, it is difficult to determine a reference position of the ink rail body and skill is required in working of this determination so that it takes much time to make this work.